I guess some of you have started to figure this out, but just to be clear as there seems to be some confusion.

The SBK is chosen by the manufacturer.

Acer have choosen to (for some of their models) base the SBK on the UID. This does not neccessarilly mean that this is the way it is for any for any devices by any other manufacturer, or even for other models from Acer. It could be that they have chosen to do it the same way, but it is highly unlikely.

Using nvflash on a Asus tf201 makes you get the SBK the same way based on UID. Toshiba SBK also the same way.

I don't know if this might be important but JB devices seems currently have no chance to managed with NVFLASH.
Every other Tegra3 device i.e. A500 can be flashed but all discussion ends with "...if you have JB installed no chance"

Using nvflash on a Asus tf201 makes you get the SBK the same way based on UID. Toshiba SBK also the same way.

At the risk of going slightly of topic, would you care to share some sources for this statement?
I can't seem to find anything but failed attemts for Toshiba (except those models without SBK). For the tf201 the only method I can find seems to rely on using a patched bootloader to, I presume, generate pre-signed RCM messages while the SBK is still available. Which would seem to be a quite convoluted way of doing things if the SBK (or the algorithm to generate it) is known.

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